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	Smart Computing Encyclopedia Entry - Adaptive Differential Pulse Code Modulation (ADPCM) (Site not responding. Last check: 2007-10-26)
		ADPCM is an advanced audio compression algorithm designed to replace the older PCM (Pulse Code Modulation) standard.
		ADPCM works its magic by using a lossy compression scheme that dis- cards unnecessary or redundant audio information and predicts how audio will vary from sample to sample.
		ADPCM compression is also used to compress music and other audio files.
	www.smartcomputing.com /editorial/dictionary/detail.asp?guid=&searchtype=1&DicID=16276&RefType=Encyclopedia (256 words)

	RFC 2422 (rfc2422) - Toll Quality Voice - 32 kbit/s ADPCM MIME Sub-type Re
		The conversion is applied to the PCM bit stream using an adaptive differential pulse code modulation (ADPCM) transcoding technique.
		MIME Definition 3.1 audio/32KADPCM CCITT Recommendation G.726 [G726] describes the algorithm recommended for conversion of a 64 kbit/s A-law or u-law PCM channel to and from a 32 kbit/s channel (this is the same algorithm as described in the deprecated G.721).
		The conversion is applied to the PCM stream using an Adaptive Differential Pulse Code Modulation (ADPCM) transcoding technique.
	www.faqs.org /rfcs/rfc2422.html (910 words)

	Technical Note TN1081: Understanding the Differences Between Apple and Windows IMA-ADPCM Compressed Sound Files
		Stereo ADPCM WAVE files have the channels interleaved differently than AIFF files and have fewer predictor bytes, which is a significant enough difference that the Apple IMA decompressor will not decompress them and produce the same sound as the Microsoft ADPCM decompressor would.
		The Microsoft ADPCM decompressor will not decompress a stereo IMA AIFF file as the Apple IMA decompressor would unless it is modified to take into account the different channel interleaving and predictor bytes.
		The step index is likely to be invalid because, depending on what the value of the predicted sample is, the high bit of the low byte of the predictor word (the least significant bit of the predicted sample) may or may not be set.
	developer.apple.com /technotes/tn/tn1081.html (1953 words)

	ADPCM Codecs (Site not responding. Last check: 2007-10-26)
		Adaptive Differential Pulse Code Modulation (ADPCM) codecs are waveform codecs which instead of quantizing the speech signal directly, like PCM codecs, quantize the difference between the speech signal and a prediction that has been made of the speech signal.
		The performance of the codec is aided by using adaptive prediction and quantization, so that the predictor and difference quantizer adapt to the changing characteristices of the speech being coded.
		Code for various ADPCM codecs, as well as the G711 A-law and u-law PCM, was released into the public domain by Sun Microsystems, Inc. Its available for FTP here.
	www-mobile.ecs.soton.ac.uk /speech_codecs/standards/adpcm.html (247 words)

	Multi-Standard ADPCM (Site not responding. Last check: 2007-10-26)
		The ADPCM megafunction, which is optimized for the Altera FLEX 10K architecture, combines the algorithm and architecture research of Amphion with the performance and implementation advantages of the FLEX 10K family.
		The ADPCM megafunction is designed in a hierarchical manner to enable the high-quality implementation achieved in the lower-level blocks, such as multipliers and adders, to be carried through to the higher-level encoder and decoder blocks.
		The G.726 standard is a fixed ADPCM algorithm for conversion to and from 64 kbits per second and 40, 32, 24, and 16 kbits per second.
	www.altera.com /products/ip/dsp/speech_audio_processing/m-amp-multi-std-adpcm.html (482 words)

	ADPCM
		The ADPCM process is only effective for correlated signals.
		The first one is an estimation loop to create all necessary side information that accompanies the coded audio data to be transmitted to the decoder.
		The coefficients are transmitted only for those sub-bands, in which the ADPCM process is active.
	www.telos.de /ADPCM.702.0.html (344 words)

	Multi-Standard ADPCM
		The ADPCM megafunction, which is optimized for the Altera FLEX 10K architecture, combines the algorithm and architecture research of Amphion with the performance and implementation advantages of the FLEX 10K family.
		The ADPCM megafunction is designed in a hierarchical manner to enable the high-quality implementation achieved in the lower-level blocks, such as multipliers and adders, to be carried through to the higher-level encoder and decoder blocks.
		The G.726 standard is a fixed ADPCM algorithm for conversion to and from 64 kbits per second and 40, 32, 24, and 16 kbits per second.
	www.altera.com.cn /products/ip/dsp/speech_audio_processing/m-amp-multi-std-adpcm.html (468 words)

	ADPCM for Highly Intelligible Speech Synthesis
		ADPCM improves upon DPCM by dynamically varying the quantization between samples depending upon their rate of change while maintaining a low bit rate, condensing 12-bit PCM samples into only 3 or 4 bits.
		In the dual-function MSM5218, the data lines D0 through D3 are bidirectional and used either for output of analyzed ADPCM data (for storage) or for input to the speech-synthesizer circuitry.
		With ADPCM, as with an analog recording, it's possible to have a voice output that reproduces the regional accents of the human speaker.
	members.tripod.com /werdav/adpcm.html (3830 words)

	IMA ADPCM (Site not responding. Last check: 2007-10-26)
		IMA ADPCM is directly supported on most Windows implementations as a native format.
		Although the quality of IMA ADPCM voice files is not great, the files are portable.
		Windows supports IMA ADPCM ".wav" files in 4-bit format only and at sample rates between 8 and 41KHz.
	www.xentec.be /products/vox_studio/help/ima_adpcm_format.htm (153 words)

	Glass, Metal and Silicium - Noise shaped ADPCM encoding
		ADPCM is a very basic audio coding scheme, and is quite fast to encode and decode.
		As it's based on encoding a difference from the predicted sample, and that prediction is based on previous samples, I already thought about a modified ADPCM encoder that would work on a window of a few samples, in order to select the optimal encoding for this whole window, instead of only considering the current sample.
		Over this window, we would do a time to frequency transform, and do an election of the best ADPCM encoded vector based on the distance from the ideal frequency based distortion.
	gabriel.mp3-tech.org /blog/index.php?entry=entry061022-113955 (492 words)

	Dialogic ADPCM Algorithm
		An ADPCM sample is presented to the decoder.
		The input ADPCM sample is also presented to the step size calculator to compute the step size estimate.
		When the ADPCM algorithm is reset the step size ss(n) is set to the minimum value (16) and the estimated waveform value X is set to zero (half scale).
	www.comptek.ru /telephony/tnotes/tt1-13.html (712 words)

	Differences Between PCM/ADPCM Wave Files Explained
		ADPCM, commonly termed as a form of compression, is a more efficient way of storing waveforms than 16-bit or 8-bit PCM.
		ADPCM stores the value differences between two adjacent PCM samples and makes some assumptions that allow data reduction.
		The distortion is easily audible in 11 kHz ADPCM files, but becomes more difficult to discern with higher sampling rates, and is virtually impossible to recognize with 44 kHz ADPCM files.
	support.microsoft.com /kb/89879 (419 words)

	Icesun Audio Converter: The Ideal Audio File Format Converter
		ADPCM (Adaptive Differential Pulse Code Modulation) is an audio compression scheme which compresses from 16-bit to 4-bit for a 4:1 compression ratio.
		Ogg Vorbis is a fully open, non-proprietary, patent-and-royalty-free, general-purpose compressed audio format for mid to high quality (8kHz-48.0kHz, 16+ bit, polyphonic) audio and music at fixed and variable bitrates from 16 to 128 kbps/channel.
		The Dialogic ADPCM format is commonly found in telephony applications, and has been optimized for low sample rate voice.
	www.icesunsoft.com /audioconverter/index.htm (1100 words)

	Emu Programming: Elsemi, maybe you can help with Yamaha ADPCM?
		The type is aica adpcm and from what ive read it is similar to the YMZ280B chip.
		Yes, AICA adpcm is the same than YMZ280B, I've done the Chankast AICA emulation and it works fine.
		volume changes often happen when you miss an adpcm sample, if you are resampling, keep in mind that you can't just skip apdcm samples, you must process all samples even if they don't get written to the output buffers due to the resampling.
	www.clrmame.com /cgi-bin/wwwthreads/showpost.pl?Board=retroemuprog&Number=3769&page=1&view=expanded&mode=flat&sb=7 (842 words)

	ADPCM: Adaptive Differential Pulse Code Modulation (Site not responding. Last check: 2007-10-26)
		The first ADPCM standardized by the CCITT is G.721 for 32 kbps.
		Later came the standards G.726 and G.727 for 40, 32, 24 and 16 kbps.
		ADPCM is used to send sound on fiber-optic long-distance lines as well as to store sound along with text, images, and code on a CD-ROM.
	www.javvin.com /wireless/ADPCM.html (70 words)

	IMA ADPCM - MultimediaWiki
		The Interactive Multimedia Association (IMA) developed an ADPCM algorithm designed to be used in entertainment multimedia applications.
		It is particularly fast to encode and decode and does not strictly require any multiplications or floating point operations.
		See the Category:IMA ADPCM Audio Codecs page for various formats used for storing the data on disk.
	wiki.multimedia.cx /index.php?title=IMA_ADPCM (725 words)

	Waves Technologies: Improved Waves ADPCM Compression Technology (Site not responding. Last check: 2007-10-26)
		Standard ADPCM compressed audio formats are now widely used by vocal mail and answering machines, as well as by the multi-media CD-ROM.
		The types of errors that ADPCM generates create audible noise on transients and fast changes of dynamics, such as speech or instrumental attacks, and mostly on high frequencies.
		The sound obtained seems to be less annoying for a long period of listening.
	www.waves.com /german/htmls/technologies/tec_improved_adpcm.htm (155 words)

	SurfWax: News, Reviews and Articles On ADPCM
		ADPCM audio and full transcoding capabilities to and from MPEG-4 and MPEG-2 are also supported.
		Even sound was compressed with ADPCM and allowed discs to hold alot more than the standard 74 minutes of audio.
		I even asked for something that was out of the ordinary- the ability to decompress ADPCM logarithms myself - and got it.
	news.surfwax.com /telecom/files/ADPCM.html (538 words)

	Dogpile Web Search: How Does ADPCM Work
		ADPCM (3) (Ref. 6), 32, 40, 40, 100, 64.
		Differential Pulse Code Modulation (ADPCM) codecs are waveform codecs which instead of quantizing...
		adpcm extension and both seem not to work.
	www.dogpile.com /info.dogpl/search/web/How%2BDoes%2BADPCM%2BWork/-/-/1/-/-/-/1/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/302349/right (256 words)

	FMOD SoundSystem :: View topic - PCM Pitch Problems & ADPCM Problems with Latest
		Note that I had these ADPCM corruption problems with 1.4.04 all the way through 1.4.15 using the default settings.
		I couldnt get it to 'pop' at the end of the sample though for #1, it sounded normal to me, but my laptop doesnt have hardware accelerated audio so it could be why.
		In my testing, our ADPCM issues were resolved in 4.04.25 (development), however the fixes were not in 4.04.24 (stable).
	www.fmod.org /forum/viewtopic.php?p=26162&sid=236540210495cd63ad8d5951c21d4f3c (562 words)

	ADPCM vs PCM -> how lossy? - Hydrogenaudio Forums
		This is because ADPCM uses prediction and a predefined index of sample values.
		How ADPCM works is that it looks at the last few samples and predicts the value of the next sample.
		To whom it may interest: The times when this might be a problem may be limited afaik, since Extigy (when properly configured) handles the direct audiostream from lets say a DVD video with its internal DTS decoder.
	www.hydrogenaudio.org /forums/index.php?showtopic=1098 (592 words)

	Untitled Document
		The Atmel Mega32 microcontroller was used to run the ADPCM algorithm, to interface with the SRAM, to output sound to the B/W TV, and to sample the output from a microphone circuit.
		Both the ADPCM encoder and decoder are run by timer0 in PWM mode to ensure regular interrupts and to free OC0 for DA conversion.
		The ADPCM algorithm itself was implemented as specified in [1] and [2] with slight modifications.
	instruct1.cit.cornell.edu /courses/ee476/FinalProjects/s2006/wc227_rks33/wc227_rks33/index.htm (3601 words)

	ADPCM - Adaptive Differential Pulse Code Modulation
		ADPCM is a acronym that can contains many meanings which are listed below.
		There may be many popular meanings for ADPCM with the most popular definition being that of Adaptive Differential Pulse Code Modulation
		If you have more information or know of another definition for ADPCM, please let us know so that we can review it and add that information to our database.
	www.auditmypc.com /acronym/ADPCM.asp (171 words)

	Asterisk.org: Developer Documentation (9 Mar 2007) (Site not responding. Last check: 2007-10-26)
		Workspace for translating ADPCM signals to signed linear.
		decode 4-bit adpcm frame data and store in output buffer
		References adpcm(), ast_trans_frameout(), f, adpcm_encoder_pvt::inbuf, ast_trans_pvt::outbuf, ast_trans_pvt::pvt, ast_trans_pvt::samples, ast_frame::samples, and adpcm_encoder_pvt::state.
	www.asterisk.org /doxygen/trunk/codec__adpcm_8c.html (465 words)

	[No title] (Site not responding. Last check: 2007-10-26)
		These ADPCM formats are supported in Creative Labs VOC files, and I believe they are used for the "Creative ADPCM" compression for WAV files.
		Their programs use about ten lines of C code per sample for decompression, but it can probably be done with less than ten assembly instructions if you work at it.
		There are two other ADPCM formats: the IMA ADPCM format, which I believe was adopted by Intel; and Microsoft ADPCM, which I know nothing about.
	homepages.cae.wisc.edu /~brodskye/tomes/adpcm.txt (511 words)

	Applying ADPCM g726
		Hi, I'm having a problem with my adpcm codec and I will appreciate any advices/suggestions given.
		I have downloaded my g726 adpcm codes onto a dsp(c5510) and I fed in an analog signal(sound card output) into the processor.
		The functionality of the adpcm codes is not in doubt as I had used the ITU test vectors on the codes and the codes were able to encode and decode correctly.
	www.dsprelated.com /groups/audiodsp/show/421.php (117 words)

	ADPCM (Site not responding. Last check: 2007-10-26)
		It is used on the Sony minidisk, and for CD-ROM which have images and other data a well a sound.
		ADPCM takes rapid samples of sound and translates them into binary code, but instead of coding an absolute measurement at every sample point, it code the difference between samples.
		ADPCM, AT, AND, Analog, A, Audio, Binary, Computer, Coding, Code, CD-ROM, Format, IT, Point
	www.hitscreen.com /dictionary/ADPCM.html (147 words)

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